This disclosure concerns an invention relating to ball clamps for engaging hitch balls such as those used on trailers and towing vehicles.
Ball- and socket-type trailer hitches are commonly used in connection with automobiles, tractor trucks, and/or other vehicles when towing trailers and other wheeled implements. Examples of such prior couplers are given in, for example, U.S. Pat. No. 2,090,113 to Dayton; U.S. Pat. No. 2,143,322 to Knobel, Jr.; U.S. Pat. No. 2,149,189 to Shaffer; U.S. Pat. No. 2,166,208 to Dayton; U.S. Pat. No. 2,170,980 to Thorp et al.; U.S. Pat. Nos. 2,178,094 and 2,204,882 to Berluti; U.S. Pat. No. 2,363,755 to Smith; U.S. Pat. No. 2,726,099 and RE 24,362 to Nunn, Jr.; U.S. Pat. No. 2,823,931 to Schrader; U.S. Pat. No. 3,130,993 to McCleary; U.S. Pat. No. 3.773,358 to Butler et al.; U.S. Pat. No. 3,954,286 to Weber, U.S. Pat. No. 4,241,935 to Vollmer et al.; U.S. Pat. Nos. 5,344,174 to Sanders; and 5,632,501 to Jackson et al. Certain features are highly desirable for incorporation within a coupler, such as high coupling strength; easy actuation by the user between the open (uncoupled) and closed (coupled) states, preferably with xe2x80x9csingle motionxe2x80x9d (i.e., solely rotational or translational) action; easy and inexpensive manufacture; and easy and inexpensive field maintenance. The coupler designs of the aforementioned patents are not believed to fulfill all of these goals, or otherwise do not achieve what is regarded to be an optimal balance between these sometimes-competing goals. Thus, the following invention has been developed to overcome the disadvantages of the prior couplers in this field.
The invention involves a ball clamp coupler which is intended to at least partially solve the aforementioned problems. To give the reader a basic understanding of some of the advantageous features of the invention, following is a brief summary of preferred versions of the ball clamp coupler, with reference being made to the drawings to allow the reader to visualize examples of the structures being described. As this is merely a summary, it should be understood that more details regarding the preferred versions may be found in the Detailed Description set forth elsewhere in this document. The claims set forth at the end of this document then define the various versions of the invention in which exclusive rights are secured.
The ball clamp coupler (item 10 in FIGS. 1 and 2) includes a coupler housing 12 having an interior wherein a coupler socket 26 is defined. The coupler socket has a bottom socket opening 28 to allow insertion of a hitch ball B (shown in phantom in FIGS. 1 and 2) within the socket opening to rest within the coupler socket. Within the coupler housing interior, a rear wall 34 is also defined adjacent the coupler socket, with the rear wall preferably having a planar configuration. A ball clamp 14 is movable within the coupler housing interior so that it may be inserted within the coupler socket 26 by varying degrees, i.e., so that it may move between an open (uncoupled) state wherein the ball clamp is removed from the coupler socket to its maximum extent (FIG. 1), and a closed (coupled) state wherein the ball clamp is inserted within the coupler socket to its maximum extent (FIG. 2). As the ball clamp moves within the coupler housing interior, it is guided against the rear wall, whereby the ball clamp is sandwiched between the hitch ball and the rear wall when the hitch ball is engaged. The rear wall prevents the hitch ball from pushing the ball clamp away from the coupler socket, and therefore the ball clamp can more strongly grasp the hitch ball.
The ball clamp 14 is driven by a clamp driving member 86, which is affixed to the ball clamp and extends from :the interior of the coupler housing 12 to its exterior at a driving member aperture 36. An actuator lever 16 is pivotally affixed to the coupler housing at a lever pivot 70, and is also at least pivotally affixed to the clamp driving member at a driving member pivot 88 (e.g., a pivot pin) outside the coupler housing. As will be discussed later in this document, the actuator lever is preferably also translatably affixed to the clamp driving member at the driving member pivot, as by situating the driving member pivot in an elongated slot 68. Thus, rotating the actuator lever about the lever pivot causes the actuator lever to rotate (and perhaps translate) with respect to the clamp driving member at the driving member pivot, thereby moving the clamp driving member and in turn moving the ball clamp between the open (uncoupled) state and the closed (coupled) state. The rear wall 34 within the coupler housing interior preferably slopes downwardly away from the coupler housing and forwardly toward the coupler socket so that as the clamp driving member urges the ball clamp downward, it will also urge the ball clamp forwardly into the coupler socket 26 to better grasp a hitch ball B therein.
The ball clamp 14 preferably includes an engagement face 94 which faces the coupler socket 26 and a lower ball clamp face 98 situated below and adjacent to the engagement face. The engagement face is configured to engage a hitch ball B within the coupler socket. The lower ball clamp face preferably slopes downwardly and rearwardly away from the coupler socket. When the lower ball clamp face is oriented in this manner, when a hitch ball encounters the lower ball clamp face, the lower ball clamp face will urge the hitch ball forwardly into the coupler socket rather than the hitch ball ineffectively pushing the ball clamp up into the interior of the coupler housing without the hitch ball moving into the coupler socket to be engaged.
While the lever pivot 70 (and thus the actuator lever 16) may be pivotally attached directly to the coupler housing 12, it is preferred to instead provide it on an actuator bracket 38 which is affixed to the exterior of the coupler housing. Where the clamp driving member 86 extends from the interior of the coupler housing to its exterior, the clamp driving member may extend from the housing adjacent the actuator bracket. The driving member pivot 88 may then affix the clamp driving member to the actuator lever adjacent the actuator bracket and outside the coupler housing.
As noted previously, the actuator lever 16 is also preferably translatably affixed to the clamp driving member 86. This may be done by providing the aforementioned slot 68 within the actuator lever, and also providing a protrusion 88 on the clamp driving member (e.g., a protruding pin) at the driving member pivot, whereby the protrusion may rotate and translate within the slot. By allowing the protrusion to translate within the slot as the actuator lever rotates, the rotating motion of the actuator lever is converted into translational motion of the clamp driving member (and thus the ball clamp 14). This efficient conversion of rotational motion to translational motion allows greater mechanical advantage, and it also reduces wear between the actuator lever and clamp driving member because the slot allows relative motion between the parts to relieve stress. Additionally, where the actuator lever is rotatably mounted to an actuator bracket 38 which is in turn mounted to the coupler housing 12, this slot compensates for imprecision in the manufacturing process: it allows minor error in placement of the actuator bracket on the coupler housing while still providing a smoothly rotating actuator lever. This helps reduce the number of discarded or refurbished couplers during manufacturing and thereby helps preserve time, manpower, and facility resources.
The actuator lever 16 may be provided with a latch 74 which can engage the coupler housing 12 (or the actuator bracket 38, if present) to fix the actuator lever (and thus the ball clamp 14) in position. For example, the latch may be rotatably mounted on the actuator lever, and may be pivotable to engage the actuator bracket to fix the actuator lever (and thus the clamp driving member 86 and ball clamp) with respect to the actuator bracket. The latch may be spring-biased to automatically engage the coupler housing or actuator bracket when released, thereby allowing automated latching and decreasing the chances of accidental release of the hitch ball B from the coupler socket 26. Preferably, the actuator lever extends rearwardly away from the coupler socket so that it does not rest above the coupler socket or obstruct a user""s view, and so that the actuator lever is shielded from inadvertent actuation (as by accidentally striking or catching on objects in its surroundings). It is preferred that the latch be situated on the side of the coupler housing (or actuator bracket) opposite the coupler socket (i.e., facing away from the juncture between the towing and towed vehicles), and it also preferably rests beneath the actuator lever so that it rests in a relatively unexposed/protected area to prevent its accidental disengagement.
The ball clamp coupler also preferably allows the ball clamp 14 to be locked into the open and/or closed states to prevent unauthorized use or theft. This may be done by providing the coupler housing 12 (or the actuator bracket 38) with a anchoring aperture 52, and providing the actuator lever 16 with a lever locking aperture 64. When the actuator lever is rotated to situate the ball clamp within the coupler socket 26 (FIG. 2), the lever locking aperture and the lever locking aperture are adjacently aligned to receive a locking member (e.g., the shackle of a padlock) therein, and therefore the ball clamp can be locked into the closed state. Additionally, the lever locking aperture may be located on the actuator lever in such a position that it is unobstructed to receive a locking member therein when the actuator lever is rotated to withdraw the ball clamp from the coupler socket 26 (FIG. 1), so that the ball clamp can be locked into the open state.
The foregoing arrangement is preferably configured so that the lever pivot 70 is unobstructed when the ball clamp is in the closed state (when it is moved to its greatest extent into the coupler socket 26, as in FIG. 2), and/or when the ball clamp is in the open state (when it is moved to its greatest extent out of the coupler socket, as in FIG. 1), so that the lever pivot is easily accessed for purposes of installation and maintenance. As an example, if the foregoing anchoring aperture 52 is provided, it may be situated and configured so that the lever locking aperture and the lever pivot are adjacently aligned when the actuator lever 16 is rotated to withdraw the ball clamp 14 from the coupler socket 26 (i.e., when the ball clamp is in the open state). This allows the lever pivot to be easily accessed through the lever locking aperture for maintenance when the actuator lever is in the open state. The coupler housing (or the actuator bracket, if provided) also preferably includes a pin access aperture 50 adjacent to the lever locking aperture, wherein the pin access aperture and the lever pivot are adjacently aligned when the actuator lever is rotated to situate the ball clamp within the coupler socket 26 (i.e., when the ball clamp is in the closed state). This also provides easier installation and maintenance.
Apart from the advantages noted above, the invention is also believed to provide several other advantages which are absent from the prior art, or which are at least presented in the prior art in an inferior manner. First, by providing the driving member pivot 88 outside the coupler housing 12 (e.g., on the actuator bracket 38), the clamp driving member 86 (and thus the ball clamp 14) may be more easily removed and replaced since the coupler housingxe2x80x94which is generally the largest structure in most ball clamp couplersxe2x80x94need not be disassembled to allow removal of the clamp driving member. This provides significant assembly and maintenance advantages over couplers having a driving member pivot within the coupler housing, since these make it difficult (if not practically impossible) to remove and replace the clamp driving member. In these ball clamp couplers, replacement of a defective ball clamp and/or clamp driving member generally requires that the coupler housing be substantially disassembled and/or replaced, which is highly problematic since the coupler housing is generally welded to a trailer.
Second, significant assembly and maintenance advantages arc also attained by situating the lever pivot 70 outside the coupler housing 12 (e.g., on the actuator bracket 38), particularly if the driving member pivot 88 is also situated outside the coupler housing 12. This arrangement allows the actuator lever 16 to be more readily removed and replaced than in prior ball clamp couplers wherein the lever pivot is within the coupler housing since the coupler housing will not require disassembly (or at least should avoid significant disassembly).
Further advantages, features, and objects of the invention will be apparent from the following detailed description of the invention in conjunction with the associated drawings.